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2018-05-17fpu/softfloat: Define floatN_silence_nan in terms of parts_silence_nanRichard Henderson
Isolate the target-specific choice to 3 functions instead of 6. The code in floatx80_default_nan tried to be over-general. There are only two targets that support this format: x86 and m68k. Thus there is no point in inventing a mechanism for snan_bit_is_one. Move routines that no longer have ifdefs out of softfloat-specialize.h. Tested-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-05-17fpu/softfloat: Define floatN_default_nan in terms of parts_default_nanRichard Henderson
Isolate the target-specific choice to 2 functions instead of 6. The code in float16_default_nan was only correct for ARM, MIPS, and X86. Though float16 support is rare among our targets. The code in float128_default_nan was arguably wrong for Sparc. While QEMU supports the Sparc 128-bit insns, no real cpu enables it. The code in floatx80_default_nan tried to be over-general. There are only two targets that support this format: x86 and m68k. Thus there is no point in inventing a value for snan_bit_is_one. Move routines that no longer have ifdefs out of softfloat-specialize.h. Tested-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-05-17fpu/softfloat: Pass FloatClass to pickNaNMulAddRichard Henderson
For each operand, pass a single enumeration instead of a pair of booleans. The commit also merges multiple different ifdef-selected implementations of pickNaNMulAdd into a single function whose body is ifdef-selected. Tested-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-05-17fpu/softfloat: Pass FloatClass to pickNaNRichard Henderson
For each operand, pass a single enumeration instead of a pair of booleans. The commit also merges multiple different ifdef-selected implementations of pickNaN into a single function whose body is ifdef-selected. Tested-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-05-17fpu/softfloat: Make is_nan et al available to softfloat-specialize.hRichard Henderson
We will need these helpers within softfloat-specialize.h, so move the definitions above the include. After specialization, they will not always be used so mark them to avoid the Werror. Tested-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-05-17fpu/softfloat: re-factor float to float conversionsAlex Bennée
This allows us to delete a lot of additional boilerplate code which is no longer needed. Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-05-17fpu/softfloat: Partial support for ARM Alternative half-precisionAlex Bennée
For float16 ARM supports an alternative half-precision format which sacrifices the ability to represent NaN/Inf in return for a higher dynamic range. The new FloatFmt flag, arm_althp, is then used to modify the behaviour of canonicalize and round_canonical with respect to representation and exception raising. Usage of this new flag waits until we re-factor float-to-float conversions. Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-05-17fpu/softfloat: Replace float_class_msnan with parts_silence_nanRichard Henderson
With a canonical representation of NaNs, we can silence an SNaN immediately rather than delay until the final format is known. Tested-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-05-17fpu/softfloat: Replace float_class_dnan with parts_default_nanRichard Henderson
With a canonical representation of NaNs, we can return the default nan directly rather than delay the expansion until the final format is known. Note one case where we uselessly assigned to a.sign, which was overwritten/ignored later when expanding float_class_dnan. Tested-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-05-17fpu/softfloat: Introduce parts_is_snan_fracRichard Henderson
Tested-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-05-17fpu/softfloat: Canonicalize NaN fractionRichard Henderson
Shift the NaN fraction to a canonical position, much like we do for the fraction of normal numbers. This will facilitate manipulation of NaNs within the shared code paths. Tested-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-05-17fpu/softfloat: Move softfloat-specialize.h below FloatParts definitionRichard Henderson
We want to be able to specialize on the canonical representation. Tested-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-05-17fpu/softfloat: Fix conversion from uint64 to float128Petr Tesarik
The significand is passed to normalizeRoundAndPackFloat128() as high first, low second. The current code passes the integer first, so the result is incorrectly shifted left by 64 bits. This bug affects the emulation of s390x instruction CXLGBR (convert from logical 64-bit binary-integer operand to extended BFP result). Cc: qemu-stable@nongnu.org Tested-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Petr Tesarik <ptesarik@suse.com> Message-Id: <20180511071052.1443-1-ptesarik@suse.com> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-05-15fpu/softfloat: Don't set Invalid for float-to-int(MAXINT)Peter Maydell
In float-to-integer conversion, if the floating point input converts exactly to the largest or smallest integer that fits in to the result type, this is not an overflow. In this situation we were producing the correct result value, but were incorrectly setting the Invalid flag. For example for Arm A64, "FCVTAS w0, d0" on an input of 0x41dfffffffc00000 should produce 0x7fffffff and set no flags. Fix the boundary case to take the right half of the if() statements. This fixes a regression from 2.11 introduced by the softfloat refactoring. Cc: qemu-stable@nongnu.org Fixes: ab52f973a50 Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-id: 20180510140141.12120-1-peter.maydell@linaro.org
2018-05-15fpu/softfloat: int_to_float ensure r fully initialisedAlex Bennée
Reported by Coverity (CID1390635). We ensure this for uint_to_float later on so we might as well mirror that. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2018-05-10softfloat: Handle default NaN mode after pickNaNMulAdd, not beforePeter Maydell
It is implementation defined whether a multiply-add of (0,inf,qnan) or (inf,0,qnan) raises InvalidaOperation or not, so we let the target-specific pickNaNMulAdd function handle this. This means that we must do the "return the default NaN in default NaN mode" check after the call, not before. Correct the ordering, and restore the comment from the old propagateFloat64MulAddNaN() that warned about this corner case. This fixes a regression from 2.11 for Arm guests where we would incorrectly fail to set the Invalid flag for these cases. Cc: qemu-stable@nongnu.org Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Tested-by: Alex Bennée <alex.bennee@linaro.org> Message-id: 20180504100547.14621-1-peter.maydell@linaro.org
2018-04-17fpu: Bound increment for scalbnRichard Henderson
Without bounding the increment, we can overflow exp either here in scalbn_decomposed or when adding the bias in round_canonical. This can result in e.g. underflowing to 0 instead of overflowing to infinity. The old softfloat code did bound the increment. Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Tested-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2018-04-16fpu/softfloat: check for Inf / x or 0 / x before /0Alex Bennée
The re-factoring of div_floats changed the order of checking meaning an operation like -inf/0 erroneously raises the divbyzero flag. IEEE-754 (2008) specifies this should only occur for operations on finite operands. We fix this by moving the check on the dividend being Inf/0 to before the divisor is zero check. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Message-id: 20180416135442.30606-1-alex.bennee@linaro.org Cc: Bastian Koppelmann <kbastian@mail.uni-paderborn.de> Reviewed-by: Bastian Koppelmann <kbastian@mail.uni-paderborn.de> Tested-by: Bastian Koppelmann <kbastian@mail.uni-paderborn.de> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2018-04-16fpu/softfloat: raise float_invalid for NaN/Inf in round_to_int_and_packAlex Bennée
The re-factor broke the raising of INVALID when NaN/Inf is passed to the float_to_int conversion functions. round_to_uint_and_pack got this right for NaN but also missed out the Inf handling. Fixes https://bugs.launchpad.net/qemu/+bug/1759264 Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Bastian Koppelmann <kbastian@mail.uni-paderborn.de> Tested-by: Bastian Koppelmann <kbastian@mail.uni-paderborn.de> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Message-id: 20180413140334.26622-3-alex.bennee@linaro.org Cc: Bastian Koppelmann <kbastian@mail.uni-paderborn.de> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2018-04-13softfloat: fix {min, max}nummag for same-abs-value inputsEmilio G. Cota
Before 8936006 ("fpu/softfloat: re-factor minmax", 2018-02-21), we used to return +Zero for maxnummag(-Zero,+Zero); after that commit, we return -Zero. Fix it by making {min,max}nummag consistent with {min,max}num, deferring to the latter when the absolute value of the operands is the same. With this fix we now pass fp-test. Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Message-id: 20180413140334.26622-2-alex.bennee@linaro.org Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2018-04-10fpu: Fix rounding mode for floatN_to_uintM_round_to_zeroRichard Henderson
We incorrectly passed in the current rounding mode instead of float_round_to_zero. Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Message-id: 20180410055912.934-1-richard.henderson@linaro.org Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2018-03-09softfloat: fix crash on int conversion of SNaNStef O'Rear
Signed-off-by: Stef O'Rear <sorear2@gmail.com> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2018-03-04softfloat: use floatx80_infinity in softfloatLaurent Vivier
Since f3218a8 ("softfloat: add floatx80 constants") floatx80_infinity is defined but never used. This patch updates floatx80 functions to use this definition. This allows to define a different default Infinity value on m68k: the m68k FPU defines infinity with all bits set to zero in the mantissa. Signed-off-by: Laurent Vivier <laurent@vivier.eu> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-Id: <20180224201802.911-4-laurent@vivier.eu>
2018-03-04softfloat: export some functionsLaurent Vivier
Move fpu/softfloat-macros.h to include/fpu/ Export floatx80 functions to be used by target floatx80 specific implementations. Exports: propagateFloatx80NaN(), extractFloatx80Frac(), extractFloatx80Exp(), extractFloatx80Sign(), normalizeFloatx80Subnormal(), packFloatx80(), roundAndPackFloatx80(), normalizeRoundAndPackFloatx80() Also exports packFloat32() that will be used to implement m68k fsinh, fcos, fsin, ftan operations. Signed-off-by: Laurent Vivier <laurent@vivier.eu> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-Id: <20180224201802.911-2-laurent@vivier.eu>
2018-02-21fpu/softfloat: re-factor sqrtAlex Bennée
This is a little bit of a departure from softfloat's original approach as we skip the estimate step in favour of a straight iteration. There is a minor optimisation to avoid calculating more bits of precision than we need however this still brings a performance drop, especially for float64 operations. Suggested-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2018-02-21fpu/softfloat: re-factor compareAlex Bennée
The compare function was already expanded from a macro. I keep the macro expansion but move most of the logic into a compare_decomposed. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2018-02-21fpu/softfloat: re-factor minmaxAlex Bennée
Let's do the same re-factor treatment for minmax functions. I still use the MACRO trick to expand but now all the checking code is common. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2018-02-21fpu/softfloat: re-factor scalbnAlex Bennée
This is one of the simpler manipulations you could make to a floating point number. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2018-02-21fpu/softfloat: re-factor int/uint to floatAlex Bennée
These are considerably simpler as the lower order integers can just use the higher order conversion function. As the decomposed fractional part is a full 64 bit rounding and inexact handling comes from the pack functions. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2018-02-21fpu/softfloat: re-factor float to int/uintAlex Bennée
We share the common int64/uint64_pack_decomposed function across all the helpers and simply limit the final result depending on the final size. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2018-02-21fpu/softfloat: re-factor round_to_intAlex Bennée
We can now add float16_round_to_int and use the common round_decomposed and canonicalize functions to have a single implementation for float16/32/64 round_to_int functions. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
2018-02-21fpu/softfloat: re-factor muladdAlex Bennée
We can now add float16_muladd and use the common decompose and canonicalize functions to have a single implementation for float16/32/64 muladd functions. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
2018-02-21fpu/softfloat: re-factor divAlex Bennée
We can now add float16_div and use the common decompose and canonicalize functions to have a single implementation for float16/32/64 versions. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
2018-02-21fpu/softfloat: re-factor mulAlex Bennée
We can now add float16_mul and use the common decompose and canonicalize functions to have a single implementation for float16/32/64 versions. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
2018-02-21fpu/softfloat: re-factor add/subAlex Bennée
We can now add float16_add/sub and use the common decompose and canonicalize functions to have a single implementation for float16/32/64 add and sub functions. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
2018-02-21fpu/softfloat: define decompose structuresAlex Bennée
These structures pave the way for generic softfloat helper routines that will operate on fully decomposed numbers. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
2018-02-21fpu/softfloat: move the extract functions to the top of the fileAlex Bennée
This is pure code-motion during re-factoring as the helpers will be needed earlier. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
2018-02-21fpu/softfloat: implement float16_squash_input_denormalAlex Bennée
This will be required when expanding the MINMAX() macro for 16 bit/half-precision operations. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
2017-06-29softfloat: define floatx80_round()Laurent Vivier
Add a function to round a floatx80 to the defined precision (floatx80_rounding_precision) Signed-off-by: Laurent Vivier <laurent@vivier.eu> Reviewed-by: Richard Henderson <rth@twiddle.net> Reviewed-by: Aurelien Jarno <aurelien@aurel32.net> Message-Id: <20170628204241.32106-5-laurent@vivier.eu>
2017-02-28softfloat: Use correct type in float64_to_uint64_round_to_zero()Peter Maydell
In float64_to_uint64_round_to_zero() a typo meant that we were taking the uint64_t return value from float64_to_uint64() and putting it into an int64_t variable before returning it as uint64_t again. Use uint64_t instead of pointlessly casting it back and forth to int64_t. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Laurent Vivier <laurent@vivier.eu> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2017-02-22softfloat: Add float128_to_uint32_round_to_zero()Bharata B Rao
float128_to_uint32_round_to_zero() is needed by xscvqpuwz instruction of PowerPC ISA 3.0. Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2017-02-22softfloat: Add float128_to_uint64_round_to_zero()Bharata B Rao
Implement float128_to_uint64() and use that to implement float128_to_uint64_round_to_zero() This is required by xscvqpudz instruction of PowerPC ISA 3.0. Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2017-02-22softfloat: Add round-to-odd rounding modeBharata B Rao
Power ISA 3.0 introduces a few quadruple precision floating point instructions that support round-to-odd rounding mode. The round-to-odd mode is explained as under: Let Z be the intermediate arithmetic result or the operand of a convert operation. If Z can be represented exactly in the target format, the result is Z. Otherwise the result is either Z1 or Z2 whichever is odd. Here Z1 and Z2 are the next larger and smaller numbers representable in the target format respectively. Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <rth@twiddle.net> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2016-09-15fpu: add mechanism to check for invalid long double formatsAndrew Dutcher
All operations that take a floatx80 as an operand need to have their inputs checked for malformed encodings. In all of these cases, use the function floatx80_invalid_encoding to perform the check. If an invalid operand is found, raise an invalid operation exception, and then return either NaN (for fp-typed results) or the integer indefinite value (the minimum representable signed integer value, for int-typed results). For the non-quiet comparison operations, this touches adjacent code in order to pass style checks. Signed-off-by: Andrew Dutcher <andrew@andrewdutcher.com> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Message-id: 1471392895-17324-1-git-send-email-andrew@andrewdutcher.com [PMM: changed "1 << 63" to "1ULL << 63" to fix compile errors] Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2016-06-24softfloat: Implement run-time-configurable meaning of signaling NaN bitAleksandar Markovic
This patch modifies SoftFloat library so that it can be configured in run-time in relation to the meaning of signaling NaN bit, while, at the same time, strictly preserving its behavior on all existing platforms. Background: In floating-point calculations, there is a need for denoting undefined or unrepresentable values. This is achieved by defining certain floating-point numerical values to be NaNs (which stands for "not a number"). For additional reasons, virtually all modern floating-point unit implementations use two kinds of NaNs: quiet and signaling. The binary representations of these two kinds of NaNs, as a rule, differ only in one bit (that bit is, traditionally, the first bit of mantissa). Up to 2008, standards for floating-point did not specify all details about binary representation of NaNs. More specifically, the meaning of the bit that is used for distinguishing between signaling and quiet NaNs was not strictly prescribed. (IEEE 754-2008 was the first floating-point standard that defined that meaning clearly, see [1], p. 35) As a result, different platforms took different approaches, and that presented considerable challenge for multi-platform emulators like QEMU. Mips platform represents the most complex case among QEMU-supported platforms regarding signaling NaN bit. Up to the Release 6 of Mips architecture, "1" in signaling NaN bit denoted signaling NaN, which is opposite to IEEE 754-2008 standard. From Release 6 on, Mips architecture adopted IEEE standard prescription, and "0" denotes signaling NaN. On top of that, Mips architecture for SIMD (also known as MSA, or vector instructions) also specifies signaling bit in accordance to IEEE standard. MSA unit can be implemented with both pre-Release 6 and Release 6 main processor units. QEMU uses SoftFloat library to implement various floating-point-related instructions on all platforms. The current QEMU implementation allows for defining meaning of signaling NaN bit during build time, and is implemented via preprocessor macro called SNAN_BIT_IS_ONE. On the other hand, the change in this patch enables SoftFloat library to be configured in run-time. This configuration is meant to occur during CPU initialization, at the moment when it is definitely known what desired behavior for particular CPU (or any additional FPUs) is. The change is implemented so that it is consistent with existing implementation of similar cases. This means that structure float_status is used for passing the information about desired signaling NaN bit on each invocation of SoftFloat functions. The additional field in float_status is called snan_bit_is_one, which supersedes macro SNAN_BIT_IS_ONE. IMPORTANT: This change is not meant to create any change in emulator behavior or functionality on any platform. It just provides the means for SoftFloat library to be used in a more flexible way - in other words, it will just prepare SoftFloat library for usage related to Mips platform and its specifics regarding signaling bit meaning, which is done in some of subsequent patches from this series. Further break down of changes: 1) Added field snan_bit_is_one to the structure float_status, and correspondent setter function set_snan_bit_is_one(). 2) Constants <float16|float32|float64|floatx80|float128>_default_nan (used both internally and externally) converted to functions <float16|float32|float64|floatx80|float128>_default_nan(float_status*). This is necessary since they are dependent on signaling bit meaning. At the same time, for the sake of code cleanup and simplicity, constants <floatx80|float128>_default_nan_<low|high> (used only internally within SoftFloat library) are removed, as not needed. 3) Added a float_status* argument to SoftFloat library functions XXX_is_quiet_nan(XXX a_), XXX_is_signaling_nan(XXX a_), XXX_maybe_silence_nan(XXX a_). This argument must be present in order to enable correct invocation of new version of functions XXX_default_nan(). (XXX is <float16|float32|float64|floatx80|float128> here) 4) Updated code for all platforms to reflect changes in SoftFloat library. This change is twofolds: it includes modifications of SoftFloat library functions invocations, and an addition of invocation of function set_snan_bit_is_one() during CPU initialization, with arguments that are appropriate for each particular platform. It was established that all platforms zero their main CPU data structures, so snan_bit_is_one(0) in appropriate places is not added, as it is not needed. [1] "IEEE Standard for Floating-Point Arithmetic", IEEE Computer Society, August 29, 2008. Signed-off-by: Thomas Schwinge <thomas@codesourcery.com> Signed-off-by: Maciej W. Rozycki <macro@codesourcery.com> Signed-off-by: Aleksandar Markovic <aleksandar.markovic@imgtec.com> Tested-by: Bastian Koppelmann <kbastian@mail.uni-paderborn.de> Reviewed-by: Leon Alrae <leon.alrae@imgtec.com> Tested-by: Leon Alrae <leon.alrae@imgtec.com> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> [leon.alrae@imgtec.com: * cherry-picked 2 chunks from patch #2 to fix compilation warnings] Signed-off-by: Leon Alrae <leon.alrae@imgtec.com>
2016-02-19fpu: Use plain 'int' rather than 'int_fast16_t' for exponentsPeter Maydell
Use the plain 'int' type rather than 'int_fast16_t' for handling exponents. Exponents don't need to be exactly 16 bits, so using int16_t for them would confuse more than it clarified. This should be a safe change because int_fast16_t semantics permit use of 'int' (and on 32-bit glibc that is what you get). Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Aurelien Jarno <aurelien@aurel32.net> Message-id: 1453807806-32698-4-git-send-email-peter.maydell@linaro.org
2016-02-19fpu: Use plain 'int' rather than 'int_fast16_t' for shift countsPeter Maydell
Use the plain 'int' type rather than 'int_fast16_t' for shift counts in the various shift related functions, since we don't actually care about the size of the integer at all here, and using int16_t would be confusing. This should be a safe change because int_fast16_t semantics permit use of 'int' (and on 32-bit glibc that is what you get). Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Aurelien Jarno <aurelien@aurel32.net> Message-id: 1453807806-32698-3-git-send-email-peter.maydell@linaro.org
2016-02-19fpu: Remove use of int_fast16_t in conversions to int16Peter Maydell
Make the functions which convert floating point to 16 bit integer return int16_t rather than int_fast16_t, and correspondingly use int_fast16_t in their internal implementations where appropriate. (These functions are used only by the ARM target.) Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Aurelien Jarno <aurelien@aurel32.net> Message-id: 1453807806-32698-2-git-send-email-peter.maydell@linaro.org
2016-02-04all: Clean up includesPeter Maydell
Clean up includes so that osdep.h is included first and headers which it implies are not included manually. This commit was created with scripts/clean-includes. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Message-id: 1454089805-5470-16-git-send-email-peter.maydell@linaro.org
2016-01-22softfloat: fix return type of roundAndPackFloat16Aurelien Jarno
The roundAndPackFloat16 function should return a float16 value, not a float32 one. Fix that. Cc: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Aurelien Jarno <aurelien@aurel32.net> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Message-id: 1452700993-6570-1-git-send-email-aurelien@aurel32.net Signed-off-by: Peter Maydell <peter.maydell@linaro.org>